By Oliver WrightThe British Government signed a secret security pact with Saudi Arabia and is now attempting to prevent details of the deal from being made public.

The Home Secretary Theresa May agreed to the so-called ‘memorandum of understanding’ with her Saudi counter-part Crown Prince Muhammad bin Nayef during a visit to the Kingdom last year.

The Home Office released no details of her trip at the time or announced that the deal had been signed. The only public acknowledgement was a year later in a Foreign Office report which obliquely referenced an agreement to “modernise the Ministry of the Interior”.

But now following a Freedom of Information request from the Liberal Democrats, who were in Government at the time, it has emerged that the agreement is far wider than has been acknowledged.

In its grounds for refusing to publish details of the memorandum the Home Office has admitted it “contains information relating to the UK’s security co-operation with Saudi Arabia”.

Releasing the document it says “would damage the UK’s bilateral relationship” with the Kingdom and potentially damage Britain’s national security.

Human rights groups have expressed alarm at the secretive nature of the deal with a regime which has been condemned for its human rights record.

In February the Kingdom adopted a new anti-terrorism law that defines terrorism as words or actions deemed by the authorities to be directly or indirectly “disturbing” to public order or “destabilizing the security of society.

In March, a series of decrees promulgated by the Interior Ministry extended Saudi Arabia’s extended the definition of further to include “calling for atheist thought” and “contacting any groups or individuals opposed to the Kingdom”, as well as “seeking to disrupt national unity” by calling for protests.